/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 */

/** \file
 * \ingroup GHOST
 * Declaration of GHOST_EventManager class.
 */

#ifndef __GHOST_EVENTMANAGER_H__
#define __GHOST_EVENTMANAGER_H__

#include <deque>
#include <vector>

#include "GHOST_IEventConsumer.h"

/**
 * Manages an event stack and a list of event consumers.
 * The stack works on a FIFO (First In First Out) basis.
 * Events are pushed on the front of the stack and retrieved from the back.
 * Ownership of the event is transferred to the event manager as soon as an event is pushed.
 * Ownership of the event is transferred from the event manager as soon as an event is popped.
 * Events can be dispatched to the event consumers.
 */
class GHOST_EventManager {
 public:
  /**
   * Constructor.
   */
  GHOST_EventManager();

  /**
   * Destructor.
   */
  ~GHOST_EventManager();

  /**
   * Returns the number of events currently on the stack.
   * \return The number of events on the stack.
   */
  GHOST_TUns32 getNumEvents();

  /**
   * Returns the number of events of a certain type currently on the stack.
   * \param type The type of events to be counted.
   * \return The number of events on the stack of this type.
   */
  GHOST_TUns32 getNumEvents(GHOST_TEventType type);

  /**
   * Pushes an event on the stack.
   * To dispatch it, call dispatchEvent() or dispatchEvents().
   * Do not delete the event!
   * \param event The event to push on the stack.
   */
  GHOST_TSuccess pushEvent(GHOST_IEvent *event);

  /**
   * Dispatches the given event directly, bypassing the event stack.
   */
  void dispatchEvent(GHOST_IEvent *event);

  /**
   * Dispatches the event at the back of the stack.
   * The event will be removed from the stack.
   */
  void dispatchEvent();

  /**
   * Dispatches all the events on the stack.
   * The event stack will be empty afterwards.
   */
  void dispatchEvents();

  /**
   * Adds a consumer to the list of event consumers.
   * \param consumer The consumer added to the list.
   * \return Indication as to whether addition has succeeded.
   */
  GHOST_TSuccess addConsumer(GHOST_IEventConsumer *consumer);

  /**
   * Removes a consumer from the list of event consumers.
   * \param consumer The consumer removed from the list.
   * \return Indication as to whether removal has succeeded.
   */
  GHOST_TSuccess removeConsumer(GHOST_IEventConsumer *consumer);

  /**
   * Removes all events for a window from the stack.
   * \param   window  The window to remove events for.
   */
  void removeWindowEvents(GHOST_IWindow *window);

  /**
   * Removes all events of a certain type from the stack.
   * The window parameter is optional. If non-null, the routine will remove
   * events only associated with that window.
   * \param   type    The type of events to be removed.
   * \param   window  The window to remove the events for.
   */
  void removeTypeEvents(GHOST_TEventType type, GHOST_IWindow *window = NULL);

 protected:
  /**
   * Removes all events from the stack.
   */
  void disposeEvents();

  /** A stack with events. */
  typedef std::deque<GHOST_IEvent *> TEventStack;

  /** The event stack. */
  std::deque<GHOST_IEvent *> m_events;
  std::deque<GHOST_IEvent *> m_handled_events;

  /** A vector with event consumers. */
  typedef std::vector<GHOST_IEventConsumer *> TConsumerVector;

  /** The list with event consumers. */
  TConsumerVector m_consumers;

#ifdef WITH_CXX_GUARDEDALLOC
  MEM_CXX_CLASS_ALLOC_FUNCS("GHOST:GHOST_EventManager")
#endif
};

#endif  // __GHOST_EVENTMANAGER_H__
